Loop-taker mechanism for sewing machines



April 10, 1956 w. SIEBRASSE 2,741,199

LOOP-TAKER MECHANISM FOR SEWING MACHINES Filed July 24, 1955 2 Sheets-Sheet l April 10, 1956 w. SIEBRASSE 2,741,199

LOOP-TAKER MECHANISM FOR SEWING MACHINES Filed July 24, 1953 2 Sheets-Sheet 2 Fig.9

In venfor LOOP-TAKER MECHANISM FOR SEWENG B IACHINES Wilhelm Siebrasse, Heepen, Germany, assignor to Atelier- Werke Aktiengesellschaft, Bielefeld, a con poration of Germany Application .iuly 24, 1953, Serial No. 372,895 Claims priority, application Germany November 14, 1952 4 Claims. (Cl. 112-232) shaft on which the case is mounted and causes the horn of the bobbin case to hit against the surfaces of the horn-receiving recess in the loop-taker guide ring.

To avoid the resulting beating noises, it has been proposed to have the driver act resiliently upon the loop taker. However, this does not do away with the impacts and noises occurring, during the pendulous oscillations of the bobbin case, between the horn and the recess of the guide ring. Only with spectacle-frame shaped loop takers in round-bobbin machines, which do not perform oscillatory movements, has it become known to make one side of the recess for the horn resilient.

it is an object of my invention to devise a stitch-forming mechanism with an oscillatory loop taker that se cures a noiseless operation to an extent heretofore unattained in mechanism of this type.

To this end, and in accordance with a feature of my invention, 1 provide the stitch-forming mechanism with resilient means that during the reciprocating motion of the driver not only dampen the impacts between driver and loop taker but also yieldingly receive the resulting blow-like pendulous movements of the bobbin-case horn.

This and more specific features of my invention will be apparent from the following description in conjunction with the drawing, in which Fig. l is an am'al view of the driver of a stitch-forming mechanism according to the invention, Fig. 2 shows one end of the driver in section and on a larger scale, and Pig. 3 is a top view of the same end of the driver;

Fig. 4 is an axial view of a modified driver, Fig. 5 shows separately one end of the driver on a larger scale, and Fig. 6 is a top view of the same end;

Fig. 7 is an axial view of the loop-taker guide ring to be used with a driver according to Figs. 1 to 3 or Figs. 4 to 6, and Fig. 8 shows part of the same ring on a larger scale;

Fig. 9 is an axial view of the entire stitch-forming mechanism including a driver according to Figs. 1 to 3 and a guide ring according to Figs. 7 and 8;

Figs. 10 and 11 are a side view and front view respectiveiy of the loop taker, while Figs. 12 and 13 are respective front and side views of the bobbin case pertaining to the mechanism of Fig. 9.

The driver 1 shown in Figs. 1 to 3 and 9 has each of its two ends 2 bifurcated by a recess 3. A bore 4 extends from the bottom of the recess inwardly and receives the two straight ends 5 of a coiled spring 6 which has several turns located in the recess and projecting away ited States Patent from the end of the driver. The spring 6 is additionally fastened by means of a cross pin 7.

In the modified design of the driver according to Figs. 4 to 6, the coiled spring 6 is disposed on a step formed by a recess 8 and is secured to the end 2 of the driver 1 by means of a fastening screw 9.

The loop-taker guide ring it), separately illustrated in Fi s. 7 and 8, has a substantially circular central opening it which, in the assembled mechanism, is concentric to the axis of driver and bobbin. The opening 11 has a recess 12 which extends outwardly from the axis and receives the end of the born 13 of the bobbin case :14 (Fig. 9). The end of horn 13 is straddled by a U-shaped portion of a leaf spring 15. Spring 15 has both ends secured to guide ring it} by respective fastening screws The heads of screws 16 are inserted into cavities of the ring, and the ends of spring 15 areinserted .into grooves 17 of the guide ring (Fig. 8). Consequently, the spring 1 and the screws in are sunken into the body f the guide ring and do not axially project therefrom.

As apparent from the assembly drawing Fig. 9, the driver 1 has its central axis coaxial with the guide ring 3% and the springs s of the driver are engageable with res ective abutment faces of the loop taker 18 (Figs. 9, 10, ll) which is guided in ring it? for rotational movement about its central bearing shaft 19. The driver 1 has an ofi-set central hub portion connected with the usual reciprocating rotary drive shaft (not illustrated) of the sewing machine. Preferably only one or only a few of the turns of each spring are eugageable with the loop taker. The bobbin case 14 (Figs. 9, 12, 13) is journalled on shaft 19. The horn 13, extending out-' wardly from the bobbin case 14, enters into recess 12 (Fig. 9) coacts with the curved portion of spring 15. During the reciprocating motion of the driver 1 about the axis of shaft 19, the springs 6 of driver 1 strike against the loop taker 18 and accelerate it by impact. As a result, the bobbin case 2.4 and the horn 13 are also subjected to an impact-wise pendulous movement due to the friction occurring between shaft 1? and the bore of the bobbin case or due to the thread passing upwardly from the bobbin. This pendulous movement of horn 13 is absorbed by the spring 15 since this spring is so mounted that there is a slight spacing between the spring and the adjacent surfaces of the recess 12 permitting the spring to yield upwardly. By virtue of the coaction between the resilient action of springs 6 and 15, the noise caused by the stitch-forming mechanism during the sewing operation is greatly reduced.

it will be understood by those skilled in the art upon a study of this disclosure that as far as the design details are concerned, my invention permits of vaiious modifications and hence may be embodied in devices other than those illustrated and described, without departing from the essence of the invention and within the scope of the claims annexed hereto.

1 clairn:

l. Stitch-forming mechanism for oscillating loop taker sewin machines, comprising a shaft, a driver rotationally reciprocable about the axis of said shaft, a loop taker coaxially movable about said axis and disposed in the path of said driver to be reciprocatingly driven thereby, a bobbin case rotatable about said axis and having a horn projecting in a direction outwardly away from said shaft, a loop-taker guide ring having an opening concentric to said axis and having a recess extending outwardly from said opening and straddling the end of said horn, first elastic means mounted on said driver and disposed between said driver and said loop taker, and second elastic means mounted on said ring and disposed in said recess and engageable by said horn end to absorb impact-like pendulous movements of said horn due to impacts of said driver upon said loop taker.

2. In astitch-forming mechanism according to claim 1, said driver having a recess in its end facing said loop taker, and said first elastic means comprising a coiled spring seated in said recess and secured to said driver; said spring having a coil portion projecting out of said recess and away from'said driver toward said loop taker to be engageable with said loop taker.

t 3. In a stitch forming mechanism according to claim 1, said first elastic means comprising a coiled spring, and

, fastening means passing through said spring and being secured to said driver for attaching said spring thereto, said spring projecting from said driver toward said loop taker and being engageable with said'loop taker.

4. "Stitch-forming mechanisrnior oscillating loop-taker V sewing machines, comprising a shaft, a driver rotationally reciprocable about the axis of said shaft, a loop-taker coaxially movable about said axis and disposed in the path of said driver to be reciprocatingly driven thereby,

a bobbin case rotatable about said axis and having a horn projecting in a direction outwardly away from said adjacent to said recess, said spring having a central 7 curved portion extending into said recess in spaced relation with respect thereto and being engageable with said end of said horn, said spring having end portions secured grooves in opposite sides of said recess in said loop-taker.

References Cited in the file of this patent UNITED STATES PATENTS 2,007,894 Goosman July 9,1935

FOREIGN PATENTS 341,756 Great Britain Jan. 22,1931

339,351 Italy Apr. 17, 1936 

